package com.ruoyi.core.util;

import com.ruoyi.core.exception.RunException;
import lombok.extern.slf4j.Slf4j;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.util.Base64;
import java.util.Random;

/**
 * @author wanghao 913351190@qq.com
 * @create 2022/7/21 11:13
 */
@Slf4j
public class CaptchaUtil {
    final static Base64.Encoder encoder = Base64.getEncoder();
    /**
     * 随机产生数字与字母组合的字符串
     */
    private static String randString = "0123456789ABCDEFGHJKLMNPQRSTUVWXYZ";

    /**
     * 图片宽
     */
    private static int width = 100;

    /**
     * 图片高
     */
    private static int height = 40;

    /**
     * 干扰线数量
     */
    private static int lineSize = 60;

    /**
     * 随机产生字符数量
     */
    private static int stringNum = 4;

    /**
     * 随机函数
     */
    private static Random random = new Random();

    /**
     * 获得字体
     */
    private static Font getFont() {
        return new Font("Fixedsys", Font.CENTER_BASELINE, 30);
    }

    /**
     * 获得颜色
     */
    private static Color getRandColor(int fc, int bc) {
        if (fc > 255) {
            fc = 255;
        }
        if (bc > 255) {
            bc = 255;
        }
        int r = fc + random.nextInt(bc - fc - 16);
        int g = fc + random.nextInt(bc - fc - 14);
        int b = fc + random.nextInt(bc - fc - 18);
        return new Color(r, g, b);
    }

    /**
     * 获取随机的字符
     */
    public static String getRandomString() {
        StringBuilder sb = new StringBuilder();
        for (int i = 1; i <= stringNum; i++) {
            sb.append(randString.charAt(random.nextInt(randString.length())));
        }
        return sb.toString();
    }

    /**
     * 生成随机图片
     */
    public static String getRandomBase64(String randomString) {
        // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        //产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
        Graphics2D g = image.createGraphics();

        //设置透明 start
        image = g.getDeviceConfiguration().createCompatibleImage(width, height, Transparency.TRANSLUCENT);
        g = image.createGraphics();
        //设置透明 end

        //字体大小
        g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));
        //字体颜色
        g.setColor(getRandColor(110, 133));
        // 绘制干扰线
        drowLine(g);
        // 绘制随机字符
        drowString(g, randomString);
        g.dispose();
//        try {
//            ImageIO.write(image, "png", new File("C:\\Users\\A\\Desktop\\tmp1\\1.png"));
//        } catch (IOException e) {
//            e.printStackTrace();
//        }
        try (ByteArrayOutputStream stream = new ByteArrayOutputStream()) {
            ImageIO.write(image, "png", stream);
            String base64 = encoder.encodeToString(stream.toByteArray());
            return "data:image/jpeg;base64," + base64;
        } catch (Exception e) {
            log.error("生成图片异常", e);
            throw new RunException("生成图片异常" + e.getMessage());
        }
    }

    /**
     * 绘制字符串
     */
    private static void drowString(Graphics g, String randomString) {
        for (int i = 0; i < randomString.toCharArray().length; i++) {
            g.setFont(getFont());
            g.setColor(new Color(random.nextInt(101), random.nextInt(111), random.nextInt(121)));
            g.translate(random.nextInt(3), random.nextInt(3));
            g.drawString(String.valueOf(randomString.charAt(i)), 20 * i + 8, 31);
        }
    }

    /**
     * 绘制干扰线
     */
    private static void drowLine(Graphics g) {
        for (int i = 0; i <= lineSize; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(13);
            int yl = random.nextInt(15);
            g.drawLine(x, y, x + xl, y + yl);
        }
    }


}
